Watch the Jump Blues 2 online guitar lesson by Jeff McErlain from Blues Survival Guide: Rhythm Edition
You will notice that my chord voicings are very simple, basically just a tritone. That is enough! I suggest with any blues try playing with just the tritones of each dominant 7th chord. These smaller voicings really help to from stepping on what other people in the band may be doing. Smaller the better for the most part. This was a great lesson for me to see how sparse a chord can be and still fill its harmonic content. Two notes, that's enough!